You can call it an open secret—or the rumor that won’t die. “Ford Plans New Pickup With Aluminum Body to Boost Mileage,” the Wall Street Journal said last night. It echoed a January story from Ward’s Auto: “Ford Puts Pedal to Metal With Aluminum F-Series Body Panels.” Both had been beaten to the punch by PickupTrucks.com, which ran a similar—if less certain—piece in November of 2010.

So will Ford actually hang aluminum bodywork on its steel-framed F-150? Yes. No. Sure. Why not? It’s like trying to give an answer to Schrödinger’s cat paradox—both opposite possibilities are true at the same time. We’re skeptical that the next F-150 will be a workman’s Jaguar XJ or Audi A8, with aluminum sheetmetal covering the side of the bed, the back of the cab, and the doors. It’d be great if Ford could cut several hundred pounds by ditching some steel, but we’re not optimistic. Here’s why:

Aluminum costs three-to-four-times as much as steel. According to Novelis, one of the biggest aluminum suppliers in the car industry, automotive aluminum runs between $4 and $6 per kg; steel is $1.30. You think Ford wants to cut into the profitability of its biggest-selling product?

Construction with aluminum still is more difficult than with steel. Manufacturers and suppliers have made a lot of progress, but factory environments still need to be cleaner, and the way aluminum deals with heating and cooling is very different. Best case scenario: Factory workers have to be trained on two metals, not one.

Bodywork and maintenance would be a headache for owners. Not every body shop is experienced and comfortable working with aluminum panels, and we expect a lot of owners to wind up having to replace dented fenders altogether rather than repairing them.

Watch out for corrosion. Aluminum is susceptible to galvanic corrosion, especially when it’s in contact with steel. Road salt doesn’t help matters, either. Cars have used aluminum panels more sparingly for years, and obviously Audi, Jaguar, and other automakers are dealing with it. But on a mass-market vehicle like an F-150, execution would have to be perfect.

Shoppers could be deterred. Even if Ford could deal with the four points above, that doesn’t mean every potential customer would believe it. Ford, GM, and Chrysler have worked long and hard to present their pickups as roadworthy M1 Abrams tanks—bulletproof, bombproof, and able to work forever. We’re not sure Ford is willing to risk that image.

Far more likely than a fully aluminum-bodied truck, we think, is that Ford will use more aluminum in more places on the next F-150. The hood already is aluminum, and we can imagine front fenders or door skins picking up more. There are other spots, beneath the sheetmetal but not directly on the frame, where aluminum could work. Other metals, like magnesium, would find task-appropriate applications as well.